Power distribution system lateral protection and method

Abstract

A fault protection system for providing protection from fault current for components and devices on a lateral line proximate to a distribution transformer in a power distribution network. The system includes a single-phase recloser having a vacuum interrupter that is controlled by a controller. In one embodiment, the recloser has an insulating body that is molded in combination with an insulating body of a bushing that is connected to the distribution transformer. In this embodiment, the controller can be powered by a current transformer within the recloser. In another embodiment, the recloser is mounted to a utility pole separate from the distribution transformer, where the controller is powered by the low voltage side of the transformer and the current transformer is eliminated. An isolated power supply is provided between the transformer and the controller to provide voltage isolation.

What is claimed is: 
     
       1. A fault protection system for providing protection from fault current in a power distribution network, the system comprising:
 a utility pole; 
 a lateral line connected to the feeder and the utility pole; 
 a switching device including a switch that is electrically coupled to the lateral line, the switch being switchable to allow and block current flow through the switching device; 
 a distribution transformer mounted to the utility pole and receiving a power signal from the switching device when the switch is closed and not receiving the power signal from the switching device when the switch is open; and wherein, 
 the distribution transformer includes a bushing having an internal conductor and an outer insulating body and the switching device includes an outer insulating body, and wherein the insulating bodies of the bushing and the switching device are molded together. 
 
     
     
       2. The system according to  claim 1  wherein the switching device is powered by the distribution transformer through an isolated power supply. 
     
     
       3. The system according to  claim 1  wherein the switch is a vacuum interrupter and the switching device includes a current sensor and a controller. 
     
     
       4. The system according to  claim 3  wherein the switching device includes a current transformer that powers the controller. 
     
     
       5. The system according to  claim 3  wherein the controller receives power from the distribution transformer. 
     
     
       6. The system according to  claim 5  further comprising an isolated power supply configured to electrically isolate the controller from a lateral line voltage at the switching device. 
     
     
       7. The system according to  claim 5  further comprising an isolated power supply configured to electrically isolate the controller from a high voltage at the switching device. 
     
     
       8. The system according to  claim 1  wherein the switching device is a single-phase recloser. 
     
     
       9. A fault protection system for providing protection from fault current in a power distribution network, the system comprising:
 a switching device including a switch that is switchable to allow and block current flow through the switching device, the switching device including an outer insulating body; and 
 a distribution transformer receiving a power signal from the switching device when the switch is closed and not receiving the power signal from the switch device when the switch is open, the distribution transformer including a bushing having a center conductor and an outer insulating body, wherein the insulating bodies of the bushing and the switching device are molded together. 
 
     
     
       10. The system according to  claim 9  wherein the switching device is a single-phase recloser including a current sensor and a controller and the switch is a vacuum interrupter. 
     
     
       11. The system according to  claim 10  wherein the switching device includes a current transformer that powers the controller. 
     
     
       12. A protection system for providing protection from fault current in a power distribution network, the system comprising:
 a switching device including a switch that is switchable to allow and block current flow through the switching device; 
 a distribution transformer receiving a power signal from the switching device when the switch is closed and not receiving the power signal from the switching device when the switch is open, wherein the switching device is powered by the distribution transformer; and wherein, 
 the distribution transformer includes a bushing having an internal conductor and an outer insulating body and the switching device includes an outer insulating body, and wherein the insulating bodies of the bushing and the switching device are molded together. 
 
     
     
       13. The system according to  claim 12  wherein the switching device is a single-phase recloser including a current sensor and a controller and the switch is a vacuum interrupter. 
     
     
       14. The system according to  claim 13  wherein the controller receives power from the distribution transformer.